Microfluidic valve apparatuses with separable actuation and fluid-bearing modules

Abstract

A valve apparatus includes a fluid-bearing module and an actuation module. The fluid-bearing module includes a substrate and a channel formed in the substrate, the channel having microfluidic dimensions. The actuation module is detachably secured to the fluid-bearing module and includes a heating/cooling element adjacent to the channel. The heating/cooling element is controllable to generate or absorb sufficient energy to cause the a material in the valve apparatus to transition from a solid phase to a liquid phase, or from a solid phase to a liquid phase, or to expand or contract, thereby providing a phase-change valve.

1. A valve apparatus comprising:
 a fluid-bearing module including
 a substrate, and 
 a channel formed in the substrate, the channel having microfluidic dimensions; and 
 
 an actuation module detachably secured to the fluid-bearing module, the actuation module including a Peltier device disposed adjacent to the channel, the Peltier device being controllable to reversibly change a phase of a material in the channel, thereby providing a phase-change valve that selectably and reversibly transitions between open and closed states responsive to actuation of the Peltier device, 
 the actuation module remaining an integral one-piece unit when detached from the fluid-bearing module. 
 
     
     
       2. The valve apparatus of  claim 1 , wherein the Peltier device comprises a four-layer structure that includes two semiconductor thermoelectric material layers providing a Peltier junction adjacent to the flow channel, and two conductive layers between which the two semiconductor thermoelectric material layers are sandwiched. 
     
     
       3. The valve apparatus of  claim 1 , wherein the Peltier device comprises a five-layer structure that includes a conductive layer adjacent to the flow channel, two semiconductor thermoelectric material layers between which the conductive layer is sandwiched, and two additional conductive layers between which the two semiconductor thermoelectric material layers are sandwiched. 
     
     
       4. The valve apparatus of  claim 1 , further comprising a thermally conductive cover over the substrate, the cover being configured to prevent fluid from the fluid-bearing module from contaminating the actuation module. 
     
     
       5. The valve apparatus of  claim 1 , wherein the substrate comprises polydimethylsiloxane (PDMS). 
     
     
       6. The valve apparatus of  claim 1 , wherein the actuation module has a substantially flat face with which the fluid-bearing module is operatively interfaced. 
     
     
       7. The valve apparatus of  claim 1 , the channel including a flow channel and a control channel that meets the flow channel at a junction,
 the material being a bi-phase material within the control channel, 
 the Peltier device being disposed adjacent to the control channel and the junction, the Peltier device being controllable to generate sufficient energy to cause the bi-phase material to transition from a solid phase to a liquid phase, 
 the valve apparatus further comprising pumping means for selectively forcing the bi-phase material either into or out of the junction when the bi-phase material is in the liquid phase. 
 
     
     
       8. The valve apparatus of  claim 7 , wherein the bi-phase material comprises a paraffin wax. 
     
     
       9. The valve apparatus of  claim 7 , wherein the pumping means includes:
 an expansion control material adjacent the bi-phase material, and 
 a heating/cooling element adjacent to the expansion control material, the heating/cooling element being controllable to transfer energy such that a volume of the expansion control material is either increased or decreased. 
 
     
     
       10. The valve apparatus of  claim 7 , wherein the pumping means includes: an electromechanical actuator. 
     
     
       11. The valve apparatus of  claim 7 , wherein the pumping means includes: an electromagnetic actuator. 
     
     
       12. The valve apparatus of  claim 7 , wherein the pumping means includes: thermal phase-change actuator. 
     
     
       13. The valve apparatus of  claim 7 , further comprising:
 an additional valve of a different type, in series with the bi-stable, phase change valve. 
 
     
     
       14. The valve apparatus of  claim 13 , wherein the additional valve comprises a Peltier actuated valve. 
     
     
       15. The valve apparatus of  claim 1 , the channel including a flow channel and a control channel that meets the flow channel at a junction,
 the material being a bi-phase material within the control channel, 
 the fluid-bearing module further comprising means for wicking the bi-phase material out of the junction when the bi-phase material is in a liquid phase; 
 the Peltier device being disposed adjacent to the control channel and the junction, the Peltier device being controllable to generate sufficient energy to cause the bi-phase material to transition from a solid phase to the liquid phase. 
 
     
     
       16. The valve apparatus of  claim 15 , wherein the bi-phase material comprises a paraffin wax. 
     
     
       17. The valve apparatus of  claim 15 , wherein the means for wicking includes:
 a reservoir adjacent the control channel; and 
 a porous material within the reservoir. 
 
     
     
       18. The valve apparatus of  claim 15 , wherein the means for wicking includes:
 a reservoir adjacent the control channel; and 
 microchannels within the reservoir. 
 
     
     
       19. The valve apparatus of  claim 1 , the channel including a flow channel and a control channel that meets the flow channel at a junction,
 the material being a bi-phase material within the control channel, 
 the fluid-bearing module further comprising a flexible diaphragm adjacent to the bi-phase material, the flexible diaphragm being biased to push the bi-phase material into the junction when the bi-phase material is in a liquid phase; 
 the Peltier device being disposed adjacent to the control channel and the junction, the Peltier device being controllable to generate sufficient energy to cause the bi-phase material to transition from a solid phase to a liquid phase. 
 
     
     
       20. The valve apparatus of  claim 19 , wherein the bi-phase material comprises a paraffin wax. 
     
     
       21. The valve apparatus of  claim 19 , wherein the flexible diaphragm comprises metal. 
     
     
       22. The valve apparatus of  claim 1 , the channel including a flow channel and a control channel that meets the flow channel at a junction,
 the material being a bi-phase material within the control channel, 
 the fluid-bearing module further comprising a flexible diaphragm adjacent to the bi-phase material, the flexible diaphragm being biased to pull the bi-phase material out of the junction when the bi-phase material is in a liquid phase; 
 the Peltier device being disposed adjacent to the control channel and the junction, the Peltier device being controllable to generate sufficient energy to cause the bi-phase material to transition from a solid phase to the liquid phase. 
 
     
     
       23. The valve apparatus of  claim 22 , wherein the bi-phase material comprises a paraffin wax. 
     
     
       24. The valve apparatus of  claim 22 , wherein the flexible diaphragm comprises metal. 
     
     
       25. A valve apparatus comprising:
 a fluid-bearing module including
 a substrate, and 
 a pattern of fluid transport elements formed in the substrate, at least one of the fluid transport elements having microfluidic dimensions, and 
 
 an actuation module detachably secured to the fluid-bearing module, the actuation module including a pattern of actuation elements, at least some of the actuation elements being disposed adjacent to corresponding fluid transport elements formed in the substrate, the at least some of the actuation elements being controllable to reversibly change a phase of a material in the corresponding adjacent fluid transport element, thereby providing a plurality of phase-change valves, each valve selectably and reversibly transitioning between open and closed states responsive to actuation of the corresponding actuation element, 
 the actuation module remaining an integral one-piece unit when detached from the fluid-bearing module. 
 
     
     
       26. The valve apparatus of  claim 25 , wherein the pattern of fluid transport elements and the pattern of actuation elements are formed such that each actuation element interfaces with a corresponding fluid transport element. 
     
     
       27. The valve apparatus of  claim 25 , wherein the pattern of fluid transport elements and the pattern of actuation elements are formed such that some actuation elements interface only with the substrate. 
     
     
       28. The valve apparatus of  claim 25 , wherein each of the fluid-bearing module and the actuation module include registration markers to ensure that the pattern of the fluid transport elements and the pattern of actuation elements are brought into a desired alignment when the actuation module is detachably secured to the fluid-bearing module. 
     
     
       29. The valve apparatus of  claim 25 , wherein the fluid-bearing module includes a thermally conductive cover over the substrate that separates the pattern of fluid transport elements from the actuation module, the cover layer being configured to prevent fluid from the fluid bearing module from contaminating the actuation module. 
     
     
       30. The valve apparatus of  claim 25 , wherein the actuation module has a substantially flat face with which the fluid-bearing module is operatively interfaced. 
     
     
       31. The valve apparatus of  claim 25 , wherein at least a subset of the actuation elements comprise Peltier devices. 
     
     
       32. The valve apparatus of  claim 31 , wherein at least one of the Peltier devices comprises a four-layer structure that includes two semiconductor thermoelectric material layers providing a Peltier junction adjacent to a fluid transport element, and two conductive layers between which the two semiconductor thermoelectric material layers are sandwiched. 
     
     
       33. The valve apparatus of  claim 31 , wherein at least one of the Peltier devices comprises a five-layer structure that includes a conductive layer adjacent to a fluid transport element, two semiconductor thermoelectric material layers between which the conductive layer is sandwiched, and two additional conductive layers between which the two semiconductor thermoelectric material layers are sandwiched.